(NEW YORK) — A pandemic of the novel coronavirus has now killed more than 693,000 people worldwide.

Over 18.2 million people across the globe have been diagnosed with COVID-19, the disease caused by the new respiratory virus, according to data compiled by the Center for Systems Science and Engineering at Johns Hopkins University. The actual numbers are believed to be much higher due to testing shortages, many unreported cases and suspicions that some national governments are hiding or downplaying the scope of their outbreaks.

Since the first cases were detected in China in December, the United States has become the worst-affected country, with more than 4.7 million diagnosed cases and at least 155,469 deaths.

Here’s how the news is developing Tuesday. All times Eastern:

7:42 a.m.: ‘We have to take this seriously,’ FDA commissioner says

The head of the U.S. Food and Drug Administration said Tuesday that the novel coronavirus outbreak is still not under control, as he urged Americans to “take this seriously.”

“This virus is still with us, and it is around the country and we’re seeing these cases come not just in the United States but around the world,” FDA Commissioner Stephen Hahn told ABC News chief anchor George Stephanopoulos in an interview on Good Morning America.

“That’s really the message we want the American people to know, that we have to take this seriously,” he added. “We need to get these case numbers down.”

Hahn called on Americans to continue practicing the “common sense public health measures” to prevent the further spread of the virus, including frequent hand washing and social distancing.

“These measures appear to be working in the areas that are hotspots,” he said.

When asked whether political considerations will be at play when the FDA takes on the role of determining whether a vaccine is both safe and effective, Hahn said they “will make that decision based upon the science and the data from the clinical trials that are going.”

“The science and data are really going to guide this decision and nothing else,” he added.

The FDA has the ability to authorize emergency use of a vaccine before the normal approval process is completed. Hahn said the agency will “expeditiously” review the data from the clinical trials as soon as its available, “whether we use the emergency use authorization path or the regular approval path.”

“Both are available to us, but our rigorous standards that we will use the safety and efficacy will be done,” he said.

The FDA will also tap a vaccine advisory committee, which Hahn said is “a standard approach.”

“We will be using that to help us make this decision,” he noted. “These are outside experts from around the country.”

6:12 a.m. UN chief warns of ‘generational catastrophe’ amid school closures

School closures due to the coronavirus pandemic in over 160 countries in mid-July affected more than one billion students, United Nations Secretary-General Antonio Guterres said Tuesday.

Meanwhile, at least 40 million children have missed out on education “in their critical pre-school year,” according to Guterres, who warned that the world faces “a generational catastrophe that could waste untold human potential, undermine decades of progress, and exacerbate entrenched inequalities.”

The U.N. chief urged schools to reopen once the local transmission of the novel coronavirus is under control.

“We are at a defining moment for the world’s children and young people,” Guterres said in a video message Tuesday. “The decisions that governments and partners take now will have lasting impact on hundreds of millions of young people, and on the development prospects of countries for decades to come.”

5:05 a.m.: Russia reports lowest daily increase in cases since April

Russia reported 5,159 new cases of COVID-19 on Monday, its lowest day-to-day increase since April 23.

The country’s coronavirus response headquarters also recorded 144 additional coronavirus-related deaths over the past 24 hours. Meanwhile, another 7,878 patients had recovered from the disease.

Overall, Russia has reported 861,423 confirmed cases of COVID-19 and 14,351 deaths since the start of the pandemic.

The country has the fourth-highest number of diagnosed cases in the world, according to a count kept by Johns Hopkins University.

3:24 a.m.: US records under 50,000 new cases for second straight day

More than 45,000 new cases of COVID-19 were identified in the United States on Monday, according to a count kept by Johns Hopkins University.

It’s the second straight day that the daily caseload is under 50,000 — a low that the country hasn’t seen for weeks. The latest day-to-day increase is also down from the country’s peak of 77,000 new cases, identified on July 16.

A total of 4,717,568 people in the United States have been diagnosed with COVID-19 since the pandemic began, and at least 155,469 of them have died, according to Johns Hopkins. The cases include people from all 50 U.S. states, Washington, D.C., and other U.S. territories as well as repatriated citizens.

By May 20, all U.S. states had begun lifting stay-at-home orders and other restrictions put in place to curb the spread of the novel coronavirus. The day-to-day increase in the country’s cases then hovered around 20,000 for a couple of weeks before shooting back up and crossing 70,000 for the first time in mid-July.

Many states have seen a rise in infections in recent weeks, with some — including Arizona, California and Florida — reporting daily records.

However, an internal memo from the Federal Emergency Management Agency shows an 8.8% decrease in new cases across the United States over the last week compared with the previous week.

That same seven-day span saw a 24% increase in deaths, according to the memo obtained by ABC News.

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